The invention relates to the subjects that are characterized in the claims, namely perfluoroalkyl-containing metal complexes with polar radicals of general formula I, process for their production and their use in NMR diagnosis and x-ray diagnosis, radiodiagnosis and radiotherapy, in MRT-lymphography and as blood-pool agents. The compounds according to the invention are quite especially suitable for intravenous lymphography, for tumor diagnosis and for infarction and necrosis imaging.
In nuclear magnetic resonance, the element fluorine is second in importance to the element hydrogen.
1) Fluorine has a high sensitivity of 83% of that of hydrogen.
2) Fluorine has only one NMR-active isotope.
3) Fluorine has a resonance frequency that is similar to hydrogenxe2x80x94fluorine and hydrogen can be measured with the same system.
4) Fluorine is biologically inert.
5) Fluorine does not occur in biological material (exception: teeth) and can therefore be used as a probe or contrast medium against a background that is free of interfering signals.
The effect of these properties is that fluorine occupies a broad space in diagnostic patent literature with magnetic nuclear resonance as a basis: fluorine-19-imaging, functional diagnosis, spectroscopy.
U.S. Pat. No. 4,639,364 (Mallinckrodt) thus proposes trifluoromethanesulfonamides as contrast media for fluorine-19-imaging:
CF3SO2NH2 
CF3SO2NHxe2x80x94CH2xe2x80x94(CHOH)4xe2x80x94CH2OH 
German Patent DE 4203254 (Max-Planck-Gesellschaft), in which an aniline derivative is proposed: 
also relates to fluorine-19-imaging.
Fluorine-19-imaging is the subject of Application WO 93/07907 (Mallinckrodt), in which phenyl derivatives are also claimed as contrast media: 
For fluorine-19-imaging, compounds of considerably simpler structure are also claimed. Thus, U.S. Pat. No. 4,586,511 (Children""s Hospital Medical Center) mentions perfluoroctylbromide
CF3(CF2)7xe2x80x94Br 
European Patent EP 307863 (Air Products) mentions perfluoro-15-crown-5-ether 
and U.S. Pat. No. 4,588,279 (University of Cincinnati, Children""s Hospital Research Foundation) mentions perfluorocarbon compounds such as perfluorocyclonanone or -octane, perfluorinated ethers such as tetrahydrofuran 
or diethers such as perfluoropropylene glycol-diether 
The compounds that are mentioned in Application WO 94/22368 (Molecular Biosystems), e.g., 
fluorine-containing radicals have the perfluorine-1H group or 1H-neopentyl group, are also used for fluorine-19-imaging.
U.S. Pat. No. 5,362,478 (VIVORX) indicates another structural type with expanded diagnostic use, in which the fluorocarbon/polymer shell combination is claimed for imaging purposes. Perfluorononane and human serum albumin are mentioned. This combination proves suitable, moreover, for using the fluorine atom as a probe for local temperature measurement and for determining the partial oxygen pressure.
Perfluorocarbons are also claimed in U.S. Pat. No. 4,586,511 for oxygen determination.
In German Patent DE 4008179 (Schering), fluorine-containing benzenesulfonamides are claimed as pH probes: 
For NMR diagnosis, compounds that contain iodine and fluorine atoms are also claimed as contrast-enhancing agents in WO 94/05335 and WO 94/22368 (both molecular biosystems): 
The fluorine-paramagnetic metal ion combination is also claimed for fluorine-19-imaging, specifically for open-chain complexes in WO 94/22368 (Molecular Biosystems) with, e.g.: 
and in EP 292 306 (TERUMO Kabushiki Kaisha) with, e.g.: 
but also for cyclic compounds, as they are mentioned in EP 628 316 (TERUMO Kabushiki Kaisha) 
The combination of fluorine atom and rare-earth metal is also claimed for NMR-spectroscopic temperature measurements in DE 4317588 (Schering): 
Ln: Rare earths: La, Pr, Dy, Eu
While no interactions occur between the two nuclei in compounds that contain the elements fluorine and iodine, intensive interaction does occur in compounds that contain fluorine and paramagnetic centers (radicals, metal ions) and that are expressed in a shortening of the relaxation time of the fluorine nucleus. The extent of this effect depends on the number of unpaired electrons of the metal ion (Gd3+ greater than Mn2+ greater than Fe3+ greater than Cu2+) and on the removal between the paramagnetic ion and the 19F-atom.
The more unpaired electrons of the metal ion are present and the closer the latter are brought to the fluorine, the greater the shortening of the relaxation time of the fluorine nucleus.
The shortening of the relaxation time as a function of the distance from the paramagnetic ion becomes apparent in all nuclei with an uneven spin number, thus also in the case of protons, and gadolinium compounds are therefore widely used as contrast media in nuclear spin tomography (Magnevist(R), Prohance(R), Omniscan(R), and Dotarem(R). 
In 1H-MR imaging (1H-MRI), however, relaxation time T1 or T2 of the protons, i.e., mainly the protons of water, and not the reaction time of the fluorine nuclei, is measured and used for imaging. The quantitative measurement for the shortening of the relaxation time is relaxivity [L/mmolxc2x7s]. Complexes of paramagnetic ions are successfully used for shortening relaxation times. In the following table, the relaxivity of several commercial preparations is indicated:
Only interactions between protons and the gadolinium ion are found in these compounds. For these contrast media in water, a relaxivity of about 4 [1/mmolxc2x7s] is thus observed.
Both fluorine compounds for fluorine-19-imaging, in which the shortened relaxation time of the fluorine nucleus is used, and non-fluorine-containing compounds, in which the relaxation time of protons of water is measured, are thus used successfully for MR imaging.
In the introduction of a perfluorocarbon-containing radical into a paramagnetic contrast medium, i.e., in the combination of properties that were previously known as suitable only for fluorine-imaging compounds, the relaxivity that relates to the protons of water also quickly increases, surprisingly enough, with compounds that were used for proton imaging. It now reaches values of 10-50 [1/mmolxc2x7s] in comparison to values of between 3.5 and 3.8 [1/mmolxc2x7s] as they were already cited for a few commercial products in the table above.
Perfluoroalkyl-containing metal complexes are already known from DE 196 034 033.1. These compounds, however, cannot be used satisfactorily for all applications. Thus, there is still a need for contrast media for the visualization of malignant tumors, lymph nodes and necrotic tissue.
Malignant tumors metastasize in clusters in regional lymph nodes, whereby multiple lymph node stations may also be involved. Lymph node metastases thus are found in about 50-69% of all patients with malignant tumors (Elke, Lymphographie (Lymphography), in: Frommhold, Stender, Thurn (eds.), Radiologische Diagnostik in Klinik und Praxis [Radiological Diagnosis in Clinical Studies and in Practice], Volume IV, Thieme Verlag Stuttgart, 7th Ed., 434-496, 1984).). The diagnosis of a metastatic attack of lymph nodes is of great importance with respect to the treatment and prognosis of malignant types of diseases. With modern imaging methods (CT, US and MRI), lymphogenous evacuations of malignant tumors are detected only inadequately, since in most cases only the size of the lymph node can be used as a diagnostic criterion. Thus, small metastases in non-enlarged lymph nodes ( less than 2 cm) cannot be distinguished from lymph node hyperplasias without a malignant attack (Steinkamp et al., Sonographie und Kernspintomographie: Differentialdiagnostik von reaktiver Lymphknoten-vergrxc3x6Berung und Lymphknoten-metastasen am Hals [Sonography and Nuclear Spin Tomography: Differential Diagnosis of Reactive Lymph Node Enlargement and Lymph Node Metastasis on the Neck], Radiol. Diagn. 33:158, 1992).
It would be desirable if a distinction could be made when using specific contrast media lymph nodes with metastatic attack and hyperplastic lymph nodes.
Direct x-ray lymphography (injection of an oily contrast medium suspension into a prepared lymph vessel) is known as an invasive method that is used only very rarely and that can visualize only small lymph drainage stations.
Fluorescence-labeled dextrans are also used experimentally in animal experiments to be able to observe lymphatic drainage after their interstitial administration. All commonly used markers for the visualization of lymph tracts and lymph nodes after interstitial/intracutaneous administration have in common the fact that they are substances with particulate character (xe2x80x9cparticulates,xe2x80x9d e.g., emulsions and nanocrystal suspensions) or large polymers (see above, WO 90/14846). Based on their inadequate local and systemic compatibility as well as their small lymphatic passageway, which causes inadequate diagnostic efficiency, the previously described preparations still do not prove optimally suitable for indirect lymphography, however.
Since the visualization of lymph nodes is of central importance for the early detection of metastatic attack in cancer patients, there is a great need for lymph-specific contrast medium preparations for diagnosis of corresponding changes of the lymphatic system.
The highest possible contrast medium concentration and high stability are just as desirable as the diagnostically relevant, most uniform possible lymphatic concentration over several lymph stations. The burden on the overall organism should be kept low by quick and complete excretion of the contrast medium. A quick start-up, if possible as early as within a few hours after the administration of contrast media, is important for the radiological practice. Good compatibility is necessary.
Largely for this reason, it is desirable to have available lymph-specific contrast media that in a diagnostic session allow both the primary tumor and a possible lymph node metastasizing to be visualized.
Another important area in medicine is the detection, localization and monitoring of necroses or infarctions. Thus, myocardial infarction is not a stationary process, but rather a dynamic process, which extends over a long period (weeks to months). The disease proceeds in about three phases, which are not strictly separated from one another, but rather are overlapping. The first phase, the development of myocardial infarction, comprises the 24 hours after the infarction, in which the destruction from the subendocardium to the myocardium progresses like a shock wave (wave front phenomenon). The second phase, the already existing infarction, comprises the stabilization of the area in which fiber formation (fibrosis) takes place as a healing process. The third phase, the healed infarction, begins after all destroyed tissue is replaced by fibrous scar tissue. During this period, an extensive restructuring takes place.
Up until now, no precise and reliable process is known that enables the current phase of a myocardial infarction to be diagnosed in a living patient. To evaluate a myocardial infarction, it is of decisive importance to know how large the proportion of the tissue that is lost in the infarction is and at what point the loss took place, since the type of therapy depends on this knowledge.
Infarctions take place not only in the myocardium, but rather also in other tissues, especially in the brain.
While the infarction can be healed to a certain extent, in a necrosis, locally limited tissue death, only the harmful sequelae for the residual organism can be prevented or at least reduced. Necroses can develop in many ways: by traumas, chemicals, oxygen deficiency or by radiation. As in infarction, the knowledge of the extent and type of a necrosis is important for further medical treatment.
Tests to improve the localization of infarctions and necroses by using contrast media in non-invasive processes, such as scintigraphy or nuclear spin tomography, therefore already took place earlier. The literature is full of reports on attempts to use porphyrins for necrosis imaging. The results that are achieved, however, paint a contradictory picture. Winkelman and Hoyes thus describe in Nature, 200, 903 (1967) that manganese-5,10,15,20-tetrakis(4-sulfonatophenyl)-porphyrin (TPPS) selectively accumulates in the necrotic portion of a tumor.
Lyon et al. (Magn. Res. Med. 4, 24 (1987)) observed, however, that manganese-TPPS is dispersed in the body, specifically in the kidney, liver, tumor and only in a small portion of the muscles. In this case, it is advantageous that the concentration in the tumor reaches its maximum only on the fourth day and only after the authors had increased the dose from 0.12 mmol/kg to 0.2 mmol/kg. The authors therefore also speak of a non-specific take-up of TPPS in the tumor. Bockhurst et al. in turn report in Acta Neurochir 60, 347 (1994, Suppl.) that MnTPPS binds selectively to tumor cells.
Foster et al. (J. Nucl. Med. 26, 756 (1985)) in turn found that 111In-5,10,15,20-tetrakis-(4-N-methyl-pyridinium)-porphyrin (TMPyP) does not accumulate in the necrotic portion, but rather in the living edge layers. It follows from the above that a porphyrin-tissue interaction exists and is obvious but not necessary.
In Circulation Vol. 90, No. 4, part 2, page 1468, Abstract No. 2512 (1994), Ni et al. report that they can visualize infarction areas with a manganese-tetraphenyl-porphyrin (Mn-TPP) and a gadolinium-mesoporphyrin (Gd-MP). In International Patent Application WO 95/31219, both substances were used in infarction and necrosis imaging. Authors Marchal and Ni write (see Example 3) that for the compound Gd-Mp, the metal content of the infarction-kidney was high, similar to that of the non-infarcted organ, but that it was nine times as large for the myocardium in the case of infarcted tissue (Example 1). It was surprising that the ratio of the signal intensities in MRI for infarcted patients was comparatively high in comparison to healthy tissue in both cases with 2.10 or 2.19. Other metalloporphyrins have been described in Application DE 19835082 (Schering AG).
Porphyrins tend to be stored in the skin, which results in a photosensitization. The sensitization can last for days, and even weeks. This in an undesirable side-effect in using porphyrins as diagnostic agents. In addition, the therapeutic index for the porphyrins is only very small, since, e.g., for Mn-TPPS, an action is used only at a dose of 0.2 mmol/kg, but LD50 is already approximately 0.5 mmol/kg.
Contrast media for necrosis and infarction imaging that are not derived from the porphyrin skeleton are described in DE 19744003 (Schering AG), DE 19744004 (Schering AG) and WO 99/17809 (EPIX). To date, however, there are still no compounds that can be used satisfactorily as contrast media in infarction and necrosis imaging.
The object of the invention was therefore to make available contrast media that can be used in particular for MRT-lymphography, but also for tumor diagnosis and necrosis and infarction imaging.
The object of the invention is achieved by the perfluoroalkyl-containing complexes with polar radicals of general formula I 
in which
Rf is a perfluorinated, straight-chain or branched carbon chain with the formula xe2x80x94CnF2nE, in which E represents a terminal fluorine, chlorine, bromine, iodine or hydrogen atom, and n stands for numbers 4-30,
K stands for a metal complex of general formula II 
in which
R1 means a hydrogen atom or a metal ion equivalent of atomic numbers 21-29, 31-33, 37-39, 42-44, 49 or 57-83, provided that at least two R1 stand for metal ion equivalents,
R2 and R3, independently of one another, represent hydrogen, C1-C7 alkyl, benzyl, phenyl, xe2x80x94CH2OH or xe2x80x94CH2OCH3, and
U represents xe2x80x94C6H4xe2x80x94Oxe2x80x94CH2-xcfx89-, xe2x80x94(CH2)1-5-xcfx89, a phenylene group, xe2x80x94CH2xe2x80x94NHCOxe2x80x94CH2xe2x80x94CH(CH2COOH)xe2x80x94C6H4-xcfx89-, xe2x80x94C6H4xe2x80x94(OCH2CH2)0-1xe2x80x94, N(CH2COOH)xe2x80x94CH2-xcfx89 or a C1-C12 alkylene group or a C7-C12xe2x80x94C6H4xe2x80x94O group that is optionally interrupted by one or more oxygen atoms, 1 to 3 xe2x80x94NHCO groups or 1- to 3 xe2x80x94CONH groups and/or is substituted with 1 to 3-(CH2)0-5 COOH groups, whereby xcfx89 stands for the binding site to xe2x80x94COxe2x80x94, or
of general formula III 
in which R1 has the above-mentioned meaning, R4 represents hydrogen or a metal ion equivalent that is mentioned under R1, and U1 represents xe2x80x94C6H4xe2x80x94Oxe2x80x94CH2-xcfx89-, whereby xcfx89 means the binding site to xe2x80x94COxe2x80x94 or of general formula IV 
in which R1 and R2 have the above-mentioned meaning or of general formula V A or V B 
in which R1 has the above-mentioned meaning, or of general formula VI 
in which R1 has the above-mentioned meaning, or of general formula VII 
in which R1 has the above-mentioned meaning, and
U1 represents xe2x80x94C6H4xe2x80x94Oxe2x80x94CH2-xcfx89-, whereby xcfx89 means the binding site to xe2x80x94COxe2x80x94,
and in radical K, optionally present free acid groups optionally can be present as salts of organic and/or inorganic bases or amino acids or amino acid amides,
G represents a radical that is functionalized in at least three places and that is selected from radicals a) to g) below 
whereby xcex1 means the binding site of G to complex K, xcex2 is the binding site of G to radical R and xcex3 represents the binding site of G to radical Z,
Z stands for 
xcex3-C(O)CH2O(CH2)2-"xgr", whereby xcex3 represents the binding site of Z to radical G, and "xgr" means the binding site of Z to perfluorinated radical Rf,
R represents a polar radical selected from complexes K of general formulas II to VII, whereby R1 here means a hydrogen atom or a metal ion equivalent of atomic numbers 20-29, 31-33, 37-39, 42-44, 49 or 57-83, and radicals R2, R3, R4, U and U1 have the above-indicated meaning
wherein when G means (he residue (c) or (d) and R is selected from general formula II or V, R shall not be identical with K of general formula I if Z stands for xcex3-C(O)CH2O(CH2)-xcex5 or the folic acid radical or
R means a carbon chain with 2-30 C-atoms that is bonded via xe2x80x94COxe2x80x94, SO2xe2x80x94 or a direct bond to radical G, in a straight line or branched, saturated or unsaturated, optionally interrupted by 1-10 oxygen atoms, 1-5 xe2x80x94NHCO groups, 1-5 xe2x80x94CONH groups, 1-2 sulfur atoms, 1-5 xe2x80x94NH groups or 1-2 phenylene groups, which optionally can be substituted with 1-2 OH groups, 1-2 NH2 groups, 1-2 xe2x80x94COOH groups, or 1-2 xe2x80x94SO3H groups, or
optionally substituted with 1-8 OH groups, 1-5 xe2x80x94COOH groups, 1-2 SO3H groups, 1-5 NH2 groups, 1-5 C1-C4 alkoxy groups, and
l, m, p, independently of one another, mean the whole numbers 1 or 2.
If the compound according to the invention is intended for use in NMR diagnosis, the metal ion of the signal-transmitting group must be paramagnetic. These are especially the divalent and trivalent ions of the elements of atomic numbers 21-29, 42, 44 and 58-70. Suitable ions are, for example, the chromium(III) ion, iron(II) ion, cobalt(II) ion, nickel(II) ion, copper(II) ion, praseodymium(III) ion, neodymium(III) ion, samarium(III) ion and ytterbium(III) ion. Because of their strong magnetic moment, gadolinium(III), terbium(III), dysprosium(III), holmium(III), erbium(III), iron(III) and manganese(II) ions are especially preferred. erbium(III), iron(III) and manganese(II) ions are especially preferred.
For the use of the compounds according to the invention in nuclear medicine (radiodiagnosis and radiotherapy), the metal ion must be radioactive. For example, radioisotopes of the elements with atomic numbers 27, 29, 31-33, 37-39, 43, 49, 62, 64, 70, 75 and 77 are suitable. Technetium, gallium, indium, rhenium, and yttrium are preferred.
If the compound according to the invention is intended for use in x-ray diagnosis, the metal ion is preferably derived from an element of a higher atomic number to achieve a sufficient absorption of x-rays. It was found that diagnostic agents that contain a physiologically compatible complex salt with metal ions of elements of atomic numbers 25, 26 and 39 as well as 57-83 are suitable for this purpose.
Manganese(II), iron(II), iron(III), praseodymium(III), neodymium(III), samarium(III), gadolinium(III), ytterbium(III) or bismuth(III) ions, especially dysprosium(III) ions and yttrium(III) ions, are preferred.
Acidic hydrogen atoms that are optionally present in R1, i.e., those that have not been substituted by the central ion, can optionally be replaced completely or partially by cations of inorganic and/or organic bases or amino acids or amino acid amides.
Suitable inorganic cations are, for example, the lithium ion, the potassium ion, the calcium ion and especially the sodium ion. Suitable cations of organic bases are, i.a., those of primary, secondary or tertiary amines, such as, for example, ethanolamine, diethanolamine, morpholine, glucamine, N,N-dimethylglucamine and especially N-methylglucamine. Suitable cations of amino acids are, for example, those of lysine, arginine, and ornithine as well as the amides of otherwise acidic or neutral amino acids.
Especially preferred compounds of general formula I are those with macrocycle K of general formulas II, III, VB or VII.
Radical U in metal complex K preferably means xe2x80x94CH2xe2x80x94 or C6H4xe2x80x94Oxe2x80x94CH2-xcfx89, whereby xcfx89 stands for the binding site to xe2x80x94COxe2x80x94.
Alkyl groups R2 and R3 in the macrocycle of general formula II can be straight-chain or branched. By way of example, methyl, ethyl, propyl, isopropyl, n-butyl, 1-methyl-propyl, 2-methylpropyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,2-dimethylpropyl can be mentioned. R2 and R3, independently of one another, preferably mean hydrogen or C1-C4 alkyl.
In a quite especially preferred embodiment, R2 stands for methyl and R3 stands for hydrogen.
The benzyl group or the phenyl group R2 or R3 in macrocycle K of general formula II can also be substituted in the ring.
Polar radical R in general formula I means complex K in a preferred embodiment, whereby the latter can also be a Ca2+ complex preferably in addition to a Gd3+ complex or an Mn2+ complex. Complexes K of general formulas II, III, VA or VII are especially preferred as polar radicals R. The latter as R1 quite especially preferably exhibit a metal ion equivalent of atomic numbers 20, 25 or 64.
In another preferred embodiment, polar radical R has the following meanings:
xe2x80x94C(O)CH2CH2SO3H
xe2x80x94C(O)CH2OCH2CH2OCH2CH2OH
xe2x80x94C(O)CH2OCH2CH2OH
xe2x80x94C(O)CH2OCH2CH(OH)CH2OH
xe2x80x94C(O) CH2NHxe2x80x94C(O)CH2COOH
xe2x80x94C(O)CH2CH(OH)CH2OH
xe2x80x94C(O) CH2OCH2COOH
xe2x80x94SO2CH2CH2COOH
xe2x80x94C(O)xe2x80x94C6H3xe2x80x94(m-COOH)2 
xe2x80x94C(O)CH2O(CH2)2xe2x80x94C6H3xe2x80x94(mxe2x80x94CCOH)2 
xe2x80x94C(O)CH2Oxe2x80x94C6H4xe2x80x94mxe2x80x94SO3H
xe2x80x94C(O)CH2NHC(O)CH2NHC(O) CH2OCH2COOH
xe2x80x94C(O)CH2OCH2CH2OCH2COOH
xe2x80x94C(O)CH2OCH2CH(OH)CH2Oxe2x80x94CH2CH2OH
xe2x80x94C(O)CH2OCH2CH(OH)CH2OCH2xe2x80x94CH(OH)xe2x80x94CH2OH
xe2x80x94C(O)CH2SO3H
xe2x80x94C(O)CH2CH2COOH
xe2x80x94C(O)CH(OH)CH(OH)CH2OH
xe2x80x94C(O)CH2O[(CH2)2O]1-9xe2x80x94CH3 
xe2x80x94C(O)CH2O[(CH2)2O]1-9xe2x80x94H
xe2x80x94C(O)CH2OCH(CH2OH)2 
xe2x80x94C(O)CH2OCH(CH2OCH2COOH)2 
xe2x80x94C(O)xe2x80x94C6H3xe2x80x94(mxe2x80x94OCH2COOH)2 
xe2x80x94COxe2x80x94CH2Oxe2x80x94(CH2)2O(CH2)2Oxe2x80x94(CH2)2O(CH2)2OCH3 
preferably xe2x80x94C(O)CH2O [(CH2)2O]4xe2x80x94CH3.
In another preferred embodiment, polar radical R means the folic acid radical.
Of the compounds of general formula I according to the invention, in addition those are preferred in which Rf means xe2x80x94CnF2n+1. n preferably stands for the numbers 4-15. Quite especially preferred are radicals xe2x80x94C4F9, xe2x80x94C6F13, xe2x80x94C8F17, C12F25 and xe2x80x94C14F29 as well as the radicals of the compounds that are mentioned in the examples.
Radical G that is functionalized in at least three places in general formula I, which represents the xe2x80x9cskeleton,xe2x80x9d means lysine radical (a) or (b) in a preferred embodiment of the invention.
Z means the linker that is indicated in general formula I, whereby the radical 
is preferred.
The perfluoroalkyl-containing metal complexes with polar radicals of general formula I 
in which K, G, R, Z, Rf, l, m and p have the above-indicated meaning, are produced, in a way that is known in the art, by a carboxylic acid of general formula IIa 
in which R5 means a metal ion equivalent of atomic numbers 21-29, 31-33, 37-39, 42-44, 49 or 57-83 or a carboxyl protective group, and R2, R3 and U have the above-mentioned meaning, or a carboxylic acid of general formula IIIa 
in which R4, R5, and U1 have the above-mentioned meaning or a carboxylic acid of general formula IVa 
in which R5 and R2 have the above-mentioned meaning or a carboxylic acid of general formula Va or Vb 
in which R5 has the above-mentioned meaning or a carboxylic acid of general formula VIa 
in which R5 has the above-mentioned meaning or a carboxylic acid of general formula VIIa 
in which R5 and U1 have the above-mentioned meanings, being reacted in optionally activated form with an amine of general formula VIII 
in which G, R, Z, Rf, m and p have the indicated meaning, in a coupling reaction and optionally subsequent cleavage of optionally present protective groups into a metal complex of general formula I, or if R5 has the meaning of a protective group, being reacted after cleavage of these protective groups in a subsequent step in a way that is known in the art with at least one metal oxide or metal salt of an element of atomic numbers 21-29, 31-33, 37-39, 42 -44, 49 or 57-83, and then, if desired, optionally present, acidic hydrogen atoms are substituted by cations of inorganic and/or organic bases, amino acid or amino acid amides.
The carboxylic acids of general formulas IIa to VIIA that are used are either known compounds or are produced according to the process described in the examples. Thus, the production of carboxylic acids of general formula IIa is known from DE 196 52 386. The production of carboxylic acids of general formula IIIa can be carried out analogously to Example 4 of this application. The production of the carboxylic acids of general formula IVa can be derived from DE 197 28 954.
A precursor for compounds of general formula VA is N3(2,6-dioxomorpholinoethyl)-N6-(ethoxycarbonylmethyl)-3,6-diaza-octanedioic acid, which is described in EP 263 059.
The compounds of general formula VB are derived from the isomeric diethylenetriamine-pentaacetic acid, which binds via the acetic acid that is on the center N atom. This DTPA is described in Patents DE 195 07 819 and DE 195 08 058.
Compounds of general formula VI are derived from N-(carboxymethyl)-N-[2-(2,6-dioxo-4-morpholinyl)-ethyl]-glycine, whose production is described in J. Am. Oil. Chem. Soc. (1982), 59 (2), 104-107.
Compounds of general formula VII are derived from 1-(4-carboxymethoxybenzyl)-ethylenediamine tetraacetic acid, whose production was described in U.S. Pat. No. 4,622,420.
The production of amines of general formula VIII is described in detail in the examples of this application and can be carried out analogously to the processes described in the examples.
It has been shown that the metal complexes according to the invention are especially suitable for NMR diagnosis and x-ray diagnosis, but also for radiodiagnosis and radiotherapy. The subject of the invention is therefore also the use of the perfluoroalkyl-containing metal complexes according to the invention with polar radicals for production of contrast media for use in NMR diagnosis and x-ray diagnosis, especially for lymphography, for tumor diagnosis, and for infarction imaging and necrosis imaging, as well as in radiodiagnosis and radiotherapy. The compounds according to the invention are extremely well suited for use in interstitial lymphography and especially in intravenous lymphography. In addition, they can also be used for visualization of the vascular space (blood-pool agents).
Subjects of the invention are also pharmaceutical agents that contain at least one physiologically compatible compound according to the invention, optionally with the additives that are commonly used in galenicals.
The compounds of this invention are distinguished by a very good systemic compatibility and a high lymph node concentration in three successive lymph node stations (which is important especially for i.v. lymphography). They are thus especially well suited for use in MRT lymphography.
The compounds according to the invention are also extremely well suited for detecting and localizing vascular diseases, since they are dispersed exclusively in the latter in the administration in the intravascular space. The compounds according to the invention make it possible, with the help of nuclear spin tomography, to distinguish between tissue that is well supplied with blood and tissue that is poorly supplied with blood and thus to diagnose an ischemia. Because of its anemia, infarcted tissue can also be distinguished from surrounding healthy or ischemic tissue, when the contrast media according to the invention are used. This is of special importance if the point is, e.g., to distinguish a myocardial infarction from an ischemia.
Compared to the macromolecular compounds previously used as blood-pool agents, such as, for example, Gd-DTPA-polylysine, the compounds according to the invention also show a higher T1 -relaxivity and thus are distinguished by an increase of signal intensity in NMR imaging. Since in addition they have an extended retention in the blood space, they can also be administered in relatively small doses (of, e.g., xe2x89xa650 xcexcmol of Gd/l of body weight). The compounds according to the invention are primarily quickly and as completely as possible eliminated from the body, however.
It was also shown that the compounds according to the invention accumulate in areas with elevated vascular permeability, such as, e.g., in tumors; they make it possible to make statements on the perfusion of tissues, provide the possibility of determining the blood volumes in tissues, to selectively shorten the relaxation times or densities of the blood and to graphically visualize the permeability of blood vessels. Such physiological data cannot be obtained by the use of extracellular contrast media, such as, e.g., Gd-DTPA (Magnevist(R)). From these considerations also arise their uses in modern imaging processes nuclear spin tomography and computer tomography: specific diagnosis of malignant tumors, early therapy control in cytostatic, antiphlogistic or vasodilatative therapy, early detection of underperfused areas (e.g., in the myocardium); angiography in vascular diseases, and detection and diagnosis of sterile or infectious inflammations.
The production of the pharmaceutical agents according to the invention is carried out in a way that is known in the art by the complex compounds according to the inventionxe2x80x94optionally with the addition of the additives that are commonly used in galenicalsxe2x80x94being suspended or dissolved in aqueous medium and then the suspension or solution optionally being sterilized. Suitable additives are, for example, physiologically harmless buffers (such as, for example, tromethamine), additives of complexing agents (such as, for example, diethylenetriaminepentaacetic acid) or weak complexes or the Ca-complexes that correspond to the metal complexes according to the invention orxe2x80x94if necessaryxe2x80x94electrolytes such as, for example, sodium chloride orxe2x80x94if necessaryxe2x80x94antioxidants, such as, for example, ascorbic acid.
If suspensions or solutions of the agents according to the invention in water or physiological hydrochloric acid solution are desired for enteral or parenteral administration or other purposes, they are mixed with one or more adjuvant(s) that are commonly used in galenicals [for example, methyl cellulose, lactose, mannitol] and/or surfactant(s) [for example, lecithins, Tween(R), Myrj(R)] and/or flavoring substance(s) for taste correction [for example, ethereal oils].
Basically, it is also possible to produce the pharmaceutical agents according to the invention without isolating the complexes. In any case, special care must be used to carry out the chelation so that the complexes according to the invention are practically free of non-complexed metal ions that have a toxic effect.
This can be ensured, for example, with the aid of color indicators, such as xylenol orange, by control titrations during the production process. The invention therefore also relates to a process for the production of the complex compounds and their salts. As a final precaution, there remains purification of the isolated complex.
In the in-vivo administration of the agents according to the invention, the latter can be administered together with a suitable vehicle, such as, for example, serum or physiological common salt solution and together with another protein, such as, for example, human serum albumin (HSA).
The agents according to the invention are usually administered parenterally, preferably i.v. They can also be administered intravascularly or interstitially/intracutaneously depending on whether bodily vessels or tissue are to be studied.
The pharmaceutical agents according to the invention preferably contain 0.1 xcexcmol-2 mol/l of the complex and are generally dosed in amounts of 0.0001-5 mmol/kg.
The agents according to the invention meet the many requirements for suitability as contrast media for nuclear spin tomography. After oral or parenteral administration, they are thus extremely well suited for enhancing the informational value of the image that is obtained with the aid of a nuclear spin tomograph. They also show the high effectiveness that is necessary to load the body with the smallest possible amount of foreign substances and the good compatibility that is necessary to maintain the non-invasive character of the studies.
The good water solubility and low osmolality of the agents according to the invention make it possible to produce highly concentrated solutions, so as to keep the volume burden of the circulatory system within reasonable limits and to offset the dilution by bodily fluids. In addition, the agents according to the invention show not only a high stability in vitro, but also a surprisingly high stability in vivo, so that a release or an exchange of the ionsxe2x80x94which are inherently toxicxe2x80x94and which are bonded to the complexes can take place only extremely slowly within the time in which the new contrast media are completely excreted again.
In general, the agents according to the invention for use as NMR diagnostic agents are dosed in amounts of 0.001-5 mmol/kg, preferably 0.005-0.5 mmol/kg.
The complex compounds according to the invention also can advantageously be used as susceptibility reagents and as shift reagents for in-vivo-NMR spectroscopy.
Based on their advantageous radioactive properties, and the good stability of the complex compounds contained therein, the agents according to the invention are also suitable as radiodiagnostic agents. Details of such a use and dosage are described in, e.g., xe2x80x9cRadiotracers for Medical Applications,xe2x80x9d CRC-Press, Boca Raton, Fla.
The compounds and agents according to the invention can also be used in positron-emission tomography, which uses positron-emitting isotopes, such as, e.g., 43Sc, 44Sc, 52Fe, 55Co, 68Ga and 86Y (Heiss, W. D.; Phelps, M. E.; Positron Emission Tomography of Brain, Springer Verlag Berlin, Heidelberg, N.Y. 1983).
The compounds according to the invention are also suitable, surprisingly enough, for differentiating malignant and benign tumors in areas without blood-brain barriers.
They are also distinguished in that they are completely eliminated from the body and thus are well-tolerated.
Since the substances according to the invention accumulate in malignant tumors (no diffusion in healthy tissue, but high permeability of tumor vessels), they can also support the radiation therapy of malignant tumors. The latter is distinguished from the corresponding diagnosis only by the amount and type of the isotope used. The purpose in this case is the destruction of tumor cells with high-energy shortwave radiation with as small a range of action as possible. For this purpose, interactions of the metals (such as, e.g., iron or gadolinium) that are contained in the complexes are used with ionizing radiation (e.g., x-rays) or with neutron rays. By this effect, the local radiation dose at the site where the metal complex is located (e.g., in tumors) is significantly increased. To produce the same radiation dose in malignant tissue, the radiation exposure for healthy tissue can be considerably reduced when using such metal complexes and thus side-effects imposing a burden for the patients are avoided. The metal-complex-conjugates according to the invention are therefore also suitable as radiosensitizing substances in radiation therapy of malignant tumors (e.g., use of Mossbauer effects or in neutron capture therapy). Suitable xcex2-emitting ions are, for example, 46Sc, 47Sc, 48Sc, 72Ga, 73Ga and 90Y. Suitably short half-lives that have xcex1-emitting ions are, for example, 211Bi, 212Bi, 213Bi and 214Bi whereby 212Bi is preferred. A suitable photon- and electron-emitting ion is xe2x80x9c158Gd, which can be obtained from 157Gd by neutron capture.
If the agent according to the invention is intended for use in the variant of radiation therapy proposed by R. L. Mills et al. (Nature Vol. 336, (1988), p. 787), the central ion must be derived from a Mossbauer isotope, such as, for example, 57Fe or 151Eu.
In the in-vivo administration of the agents according to the invention, the latter can be administered together with a suitable vehicle, such as, for example, serum, or physiological common salt solution and together with another protein, such as, for example, human serum albumin. In this case, the dosage depends on the type of cellular disorder, the metal ion that is used and the type of imaging method.
The agents according to the invention are usually administered parenterally, preferably i.v. They can alsoxe2x80x94as already discussedxe2x80x94be administered intravascularly or interstitially/intracutaneously depending on whether bodily vessels or tissue are to be studied.
The agents according to the invention are extremely well suited as x-ray contrast media, whereby it is especially to be emphasized that no displays of the anaphylaxis-like reactions known from the iodine-containing contrast media can be detected in biochemical-pharmacological studies with them. Because of the advantageous absorption properties in the areas of higher tube voltages, they are especially valuable for digital subtraction techniques.
In general, the agents according to the invention for use as x-ray contrast media analogously to the meglumine-diatrizoate example are dosed in amounts of 0.1-5 mmol/kg, preferably 0.25-1 mmol/kg.
In particular, higher blood concentrations are achieved with the compounds according to the invention than with extracellular contrast media. They are dispersed after i.v. administration only into the intravascular space and thus have a decisive advantage compared to the extracellular contrast media.
Embodiments